In MIUI, you can't select a folder on Sketchub when granting permission to download Sketchware and Sketchware Pro projects. Please fixed this issue for Mi users.
Sorry, it is known issue. Actually it is MIUI bug (https://stackoverflow.com/a/34045627/9300428) and we can't ask full device permission like Sketchware Pro does as it is questionable by Google playstore's new policies. We are trying to find possible way to solve this issue.